The present invention relates to organic coatings, and particularly, to water-resistant organic polymer coatings for use in water heaters. Porcelain enamel coatings traditionally used in hot water tanks and heaters are subject to corrosion and dissolution by hot water. In a water heater or water tank, once the porcelain enamel coating protecting a metal substrate is dissolved through to the substrate, then the substrate corrodes rapidly and is perforated through. At this point the water heater must be replaced.